Delayed hemolytic transfusion reaction due to anti-Go(a), an antibody against the low-prevalence Gonzales antigen.

Go(a) (D(Cor)) is a low-frequency antigen in the Rh system found on red cells lacking part of the D mosaic (category IVa). Anti-Go(a) has not been previously reported to cause hemolytic transfusion reactions. A 27-year-old African American male with sickle-cell disease, maintained on chronic transfusion, was noted to have dark plasma during an erythrocytapheresis, procedure, and the pretransfusion hemoglobin was noted to be 1 g/dl lower than 4 weeks before (with hyperbilirubinemia and a significantly increased LDH). Polyspecific direct antiglobulin test (DAT) was weakly positive (C3-weak, IgG-weak), and indirect antiglobulin tests (IATs) performed on the serum (pre- and posttransfusion reaction) and a red blood cell (RBC) eluate from the postreaction sample were negative. A segment from one of the four implicated units from the prior month's transfusion was strongly reactive at 37 degrees C and using anti-human globulin (AHG) when crossmatched with the postreaction serum and the eluate. The postreaction serum, screened with a panel of red cells positive for low-prevalence antigens, reacted with three Go(a+) cells. The implicated unit was reactive with a previously identified anti-Go(a) serum.